The unicode property indicates whether or not the "u" flag is used with a regular expression. unicode is a read-only property of an individual regular expression instance.

Property attributes of RegExp.prototype.unicode
Writable no
Enumerable no
Configurable yes


The value of unicode is a Boolean and true if the "u" flag was used; otherwise false. The "u" flag enables various Unicode-related features. With the "u" flag, any Unicode code point escapes will be interpreted as such, for example.

You cannot change this property directly. It is read-only.


Using the unicode property

var regex = new RegExp('\u{61}', 'u');

console.log(regex.unicode); // true


Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'RegExp.prototype.unicode' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of 'RegExp.prototype.unicode' in that specification.
Living Standard  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic Support5012146 No3710
FeatureAndroidChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic Support (Yes)50 (Yes)46 No3710

1. Case folding is implemented in version 13

See also

Document Tags and Contributors

 Contributors to this page: fscholz, jameshkramer, kdex, valtlai, arai
 Last updated by: fscholz,